The MLDL2000V2 is a new version of the MLDL2000 with the addition of mass storage. I have been able to do some testing lately. The result is that I will not use USB for mass storage, due to the power consumption of the USB media itself. This turned out to be very unpredictable and would drain the HP41 batteries ver fast. This would only work with an external power source or with the MLDL connected to USB, and that is not really practical.

I have done experiments with SD cards using a different controller and the additional power can be much better controlled. Also the media use very limited power.

SO now I have a few other choices to make, and would like to have the feedback from the forum:

1. SD card or microSD?
Both are possible, even inside a cardreader shell.

2. Possible inside a cardreader shell or external housing?
The current MLDL2000 fits inside a cardreader shell. One issue is that there are no more shells available, unless users choose to sacrifice their cardreader. It also appears that it is not possible to upgrade the MLDL2000 to V2 by only replacing the USB print. I am afraid that at least also the CPLD print (the most expensive part) must be replaced due to the more complicated interface between the CPLD and the SD card controller. When I design the new MLDL2000V2 for an external housing only one PCB is needed and the cost will be less. I expect that the PCB will be about 60*90 mm, so the housing will be slightly larger. Of course a cable with module connector (and module housing) is required for connection to the HP41.

as you know, I am a fierce MLDL2000 enthusiast (have two already, one is still disassembled), and I have serious reasons to go ahead and have a third unit, the V2-series being the target, now. So:

Quote: SD card or microSD?

Based on newer µSD cards, their prices and reliability (have a 1Gb µ-SD with adapter running fine in my HP50G), I guess it would not be a bad choice. But I must consider that chances are other users prefer having a regular SD card shelter, so lower-capable, earlier SD cards may be used as well (I have two 256MB SD cards I could use, too). In time: what would be the system capacity for such SD access? So, µSD card or regular SD card should not be an issue for me.

Quote:Possible inside a cardreader shell or external housing?

I'd go for a external housing with the cable. The problem would be to design a trustable connector, or use a spare module taken from a single density memory module. The card reader shell has many advantages, mostly portability, but it does not allow the use of ports 1 and 2. Consider having a HEPAX emulator with 32KRAM, and you want the HPIL plus regular printer... although possible, you should use one or the other with the card reader shell. If using an external module, you could go ahead with them all.

Quote:
1. SD card or microSD?
Both are possible, even inside a cardreader shell.

The one with the least power consumtion. Battery life is my #1 priority.

Quote:
2. Possible inside a cardreader shell or external housing?
The current MLDL2000 fits inside a cardreader shell. One issue is that there are no more shells available, unless users choose to sacrifice their cardreader. It also appears that it is not possible to upgrade the MLDL2000 to V2 by only replacing the USB print. I am afraid that at least also the CPLD print (the most expensive part) must be replaced due to the more complicated interface between the CPLD and the SD card controller. When I design the new MLDL2000V2 for an external housing only one PCB is needed and the cost will be less. I expect that the PCB will be about 60*90 mm, so the housing will be slightly larger. Of course a cable with module connector (and module housing) is required for connection to the HP41.

Inside a card reader shell. Space of the whole system is my second priority.

I haven't got an MLDL2000 yet but would like to buy the V2. I wish an external housing and SD card. I have an old MATH module to build the connector. Many thanks for your continued developments for the HP-41.

I have been looking for a card reader just for this purpose. How much would it cost to have the card-reader shell (or even a regular module shell) copied, both in NRE and the per-piece cost after that? I'm sure you could sell a lot of shells to people who want to use them for things other than the MLDL2000. I would guess the NRE would be about $3000. How many MLDL2000's do you expect to sell, especially if availability of the card-reader shell is no longer an issue?

Personally I’d prefer building it into a card reader shell (I didn’t collect some shells for nothing you know ;-)
As both microSD and miniSD can be converted into normalSD with an adapter, an interface for the latter may be more versatile. On the other hand, microSD already ranges up to 4GB (!), which seems way enough for an HP-41C to me.

While on a plane earlier this week I had some time to think about this and make some sketches. It looks like it will be possible after all to only replace the USB controller and make everything fir inside a cardreader shell. SD or microSD is still open, but not very important at this time.
The changes in both firmware and software will not be trivial, but certainly not impossible.

The PCB's for the CPLD and Interface will be changed anyway, but can be 100% compatible, with a few errors fixed and one or two extra features. For those wishing to use an external box (if you do not have a cradreader shell) I will provide a PCB that works as a carriercard for the other PCB's and provides the necessary interconnections.

I am not financially able to buy a whole new MLDL2000 V2, but a USB board replacement is still doable cost-wise. Based upon this still being a possibility, and this new board will STILL have USB connectivity to the computer for MLDL2000 data manipulation, my preferances are:

1. Card Reader Case installation.
2. uSD card, with adjustable/expandable addressing capable of accomodating future larger uSD cards. Reason for this preferance over other SD sizes is strictly one of size - I'm sure Read/Write current drain is the same for all.

I would like to know what the "...few fixed errors.." and "...one or two extra features..." are. If these are significant and will make V1 systems outdated and incompatible with future ML2K PC software and features/capability, then I may have to give up on this project - I won't be able to keep up with the additional upgrade costs. If however, these are truly insignificant upgrades and ONLY being incorporated due to a new production run requiring different parts/board layouts caused by parts nonavailability, with no impact on support software compatibility between versions, then I am fully behind this project. I will gladly purchase the new, upgraded USB board when available.

I am very excited about the possibility of having Mass Storage capability added to the MLDL2000, and the uSD card is an excellent, compact storage unit.

The V2 will be possible with the USB board only (pending some tests that I have to do). The updates on the other boards that I have planned are fixing some mistakes, but certainly not big functional changes, just a few minor things. These will include slightly better power management, LED's and extra I/O (for which no functions are defined yet). The V1 systems will be fully compatible with the V2 units if the mass storage is not used.